Logging communication using LogWriter 

Communication logs are very useful when troubleshooting issues at the SFTP protocol or communication level. Whenever you run into a problem, a log makes it possible to see what is going on.

To start logging, just add the following line into your code (just after creating the Sftp object):

// create an SFTP object
var sftp = new Rebex.Net.Sftp();

// start logging to a file
sftp.LogWriter = new Rebex.FileLogWriter(@"C:\MyData\log.txt");

' create an SFTP object
Dim sftp As New Rebex.Net.Sftp()

' start logging to a file
sftp.LogWriter = New Rebex.FileLogWriter("C:\MyData\sftp.log.txt")

A sample log file:

2013-03-13 11:06:23.188 Opening log file.
2013-03-13 11:06:23.189 Using FileLogWriter version 2.0.2700.0.
2013-03-13 11:06:23.193 INFO Sftp(4)[34] Info: Connecting to testserver.local:22 using Sftp 3.0.2700.0.
2013-03-13 11:06:23.203 INFO Sftp(4)[34] SSH: Negotiation started.
2013-03-13 11:06:23.243 INFO Sftp(4)[34] SSH: Negotiation finished.
2013-03-13 11:06:23.243 INFO Sftp(4)[34] Info: Server: SSH-2.0-OpenSSH_6.0p1 Debian-3
2013-03-13 11:06:23.243 INFO Sftp(4)[34] Info: Fingerprint: e2:29:05:cd:7a:59:ee:03:fa:03:f5:72:61:77:e3:1c
2013-03-13 11:06:23.244 INFO Sftp(4)[34] Info: Cipher info: SSH 2.0, DiffieHellmanGroupExchangeSHA256, DSS, aes256-ctr/aes256-ctr

Log verbosity levels 

There are several levels of log verbosity:

• Error - logs error messages only
• Info - default level; logs important informative messages as well
• Debug - logs all messages useful for debugging purposes
• Verbose - very detailed log for advanced analysis; logs content of communication packets
  Warning: At the Verbose level, user credentials are written to the log as well.

To specify a log level, just pass an argument to FileLogWriter's constructor:

// start logging to a file at debug level
sftp.LogWriter = new Rebex.FileLogWriter(
    @"C:\MyData\log.txt", Rebex.LogLevel.Debug);

' start logging to a file at debug level
sftp.LogWriter = New Rebex.FileLogWriter(
    "C:\MyData\sftp.log.txt", Rebex.LogLevel.Debug)

Built-in log writers 

Text file

To log into a text file, use FileLogWriter:

// start logging to a file at debug level
sftp.LogWriter = new Rebex.FileLogWriter(
    @"C:\MyData\log.txt", Rebex.LogLevel.Debug);

' start logging to a file at debug level
sftp.LogWriter = New Rebex.FileLogWriter(
    "C:\MyData\sftp.log.txt", Rebex.LogLevel.Debug)

.NET trace listener

To log to .NET Trace Listeners, use TraceLogWriter:

// start logging to subscribed trace listeners
sftp.LogWriter = new Rebex.TraceLogWriter(Rebex.LogLevel.Debug);

' start logging to subscribed trace listeners
sftp.LogWriter = New Rebex.TraceLogWriter(Rebex.LogLevel.Debug)

Standard output stream

To log to the standard output stream, use ConsoleLogWriter:

// start logging to the standard output stream at debug level
sftp.LogWriter = new Rebex.ConsoleLogWriter(Rebex.LogLevel.Debug);

' start logging to the standard output stream at debug level
sftp.LogWriter = New Rebex.ConsoleLogWriter(Rebex.LogLevel.Debug)

Logging to multiple log writers

To log to more log writers at the same time, use TeeLogWriter:

var consoleLogWriter = new Rebex.ConsoleLogWriter(Rebex.LogLevel.Debug);
var fileLogWriter = new Rebex.FileLogWriter(@"C:\MyData\log.txt", Rebex.LogLevel.Info);

// start logging to both console and file log writers
sftp.LogWriter = new Rebex.TeeLogWriter(consoleLogWriter, fileLogWriter);

Dim consoleLogWriter = New Rebex.ConsoleLogWriter(Rebex.LogLevel.Debug)
Dim fileLogWriter = New Rebex.FileLogWriter("C:\MyData\log.txt", Rebex.LogLevel.Debug)

' start logging to both console and file log writers
sftp.LogWriter = New Rebex.TeeLogWriter(consoleLogWriter, fileLogWriter)

Writing custom log writers 

// Sample log writer that logs to the standard error output stream
public class MyLogWriter : LogWriterBase
{
    protected override void WriteMessage(string message)
    {
        Console.Error.WriteLine("Rebex: {0}", message);
    }
}

' Sample log writer that logs to the standard error output stream
Public Class MyLogWriter
    Inherits LogWriterBase

    Protected Overrides Sub WriteMessage(message As String)
        Console.Error.WriteLine("Rebex: {0}", message)
    End Sub

End Class